MCP Server

The lc29h-mcp server exposes the full LC29H GNSS module capability set through the Model Context Protocol — 20 tools and 3 resources that allow LLMs to interact with GNSS hardware through natural language. Position queries, constellation configuration, RTK correction streaming, dead reckoning, power management, and base station survey-in are all available as structured tool calls.

Installation

Published package

uvx lc29h-mcp

From source

git clone https://git.supported.systems/warehack.ing/lc29h
cd lc29h
uv sync
uv run lc29h-mcp

Environment Variables

Variable	Default	Description
LC29H_PORT	/dev/ttyS0	Serial port path to the LC29H module
LC29H_BAUD	115200	Serial baud rate

Add to Claude Code

claude mcp add lc29h -- uvx lc29h-mcp

Or add to any MCP-compatible client’s config:

{
  "mcpServers": {
    "lc29h": {
      "command": "uvx",
      "args": ["lc29h-mcp"]
    }
  }
}

To pass environment variables (for a non-default serial port, for example):

{
  "mcpServers": {
    "lc29h": {
      "command": "uvx",
      "args": ["lc29h-mcp"],
      "env": {
        "LC29H_PORT": "/dev/ttyUSB0"
      }
    }
  }
}

Available Capabilities

The MCP server organizes its 20 tools into six functional groups, with 3 resources for lightweight status polling.

Position and Status

Core tools for reading the module’s current state. These work on all LC29H variants.

Tool	Parameters	Returns
get_position	none	latitude, longitude, altitude, fix_type, satellites, hdop, speed_knots, course, timestamp
get_satellites	none	List of satellite objects with prn, elevation, azimuth, snr, constellation, used_in_fix
get_module_info	none	model, firmware_version, build_date, build_time, chip_model, chip_version

The get_position tool returns a snapshot from the continuously-parsed NMEA stream. The fix_type field reports NO_FIX, GPS, DGPS, RTK_FIXED, RTK_FLOAT, or DR depending on the module’s current solution quality. HDOP (Horizontal Dilution of Precision) values below 1.0 indicate excellent geometry; values above 5.0 suggest poor satellite distribution.

The get_module_info tool sends both PAIR021 and PQTMVERNO proprietary commands to retrieve complete hardware and firmware identification. The model string encodes the variant (e.g., LC29HDA for the RTK-only variant).

Dual-band satellite data

The LC29H is a dual-frequency (L1+L5) receiver. The underlying satellite model tracks signal_id (NMEA 4.11 signal identifier, 0-8) and band (human-readable name like L1, L5, B1I, B2a) for each satellite observation. The get_satellites tool currently returns prn, elevation, azimuth, snr, constellation, and used_in_fix. The CLI (lc29h satellites) displays the full dual-band view with per-band SNR columns when signal ID data is present.

Configuration

Tools for tuning the module’s GNSS engine. Changes take effect immediately but revert on reboot unless persisted with save_config.

Tool	Parameters	Description
configure_constellations	gps, glonass, galileo, beidou, qzss (all bool, default True)	Enable or disable individual GNSS constellations. At least one must remain enabled.
set_fix_rate	ms (int, default 1000)	Position fix interval in milliseconds. Range: 100ms (10 Hz) to 10000ms (0.1 Hz). Higher rates consume more power.
save_config	none	Persist all current settings to flash memory. Sends both PAIR and PQTM save commands.
restart_module	mode (str, default "hot")	Restart the GNSS engine. hot keeps all data (~1s TTFF), warm clears ephemeris (~30s TTFF), cold clears everything (~60s TTFF).

Tip

After making configuration changes, call save_config to persist them across power cycles. The module maintains two independent configuration stores (PAIR and PQTM), and save_config writes to both.

NTRIP (RTK Corrections)

Tools for connecting to NTRIP casters that stream RTCM3 correction data. RTK corrections enable centimeter-level positioning on the DA and BA variants.

Tool	Parameters	Description
ntrip_connect	host (str), port (int, default 2101), mountpoint (str, default ""), username (str, default ""), password (str, default "")	Connect to an NTRIP caster and begin streaming RTCM3 corrections to the module.
ntrip_status	none	Returns connected boolean indicating current NTRIP connection state.
ntrip_disconnect	none	Disconnect from the NTRIP caster and cancel the RTCM forwarding task.

Source table discovery: When ntrip_connect is called with an empty mountpoint, it fetches and returns the caster’s source table instead of connecting. This returns a list of available mount points with their format, navigation system, and other metadata — useful for discovering what corrections are available from a given caster.

NTRIP protocol auto-detection

The NTRIP client auto-detects the caster’s protocol version. It attempts NTRIP 2.0 (HTTP/1.1 with Ntrip-Version: Ntrip/2.0 header) first, then falls back to NTRIP 1.0 (HTTP/1.0, ICY response) if the caster rejects the 2.0 request. This covers the full range of public and commercial casters without manual protocol configuration. The client also sends GGA position updates to the caster for Virtual Reference Station (VRS) support.

Survey-in (BS Variant)

Tools for establishing a base station. The BS variant can average its position over time to determine a precise fixed location, then output RTCM3 corrections for nearby RTK rovers.

Tool	Parameters	Description
survey_in_start	duration_s (int, default 3600), accuracy_m (float, default 1.0)	Start position averaging. The module computes a mean position over the specified duration with the target accuracy threshold.
survey_in_status	none	Returns active, valid, duration_s, mean_accuracy_m, ECEF coordinates (ecef_x, ecef_y, ecef_z), and WGS84 conversion (latitude, longitude, altitude_m).

The survey-in completes when both the duration has elapsed and the computed mean position meets the accuracy threshold. Longer durations and tighter accuracy targets produce more precise base station coordinates. A typical survey-in for sub-meter accuracy runs 1 hour; centimeter-level base station positioning may require 24 hours or more.

Dead Reckoning (BA/CA Variants)

Dead reckoning fuses GNSS with onboard inertial sensors (accelerometer and gyroscope) to maintain continuous positioning through signal gaps such as tunnels and urban canyons.

Tool	Parameters	Description
dead_reckoning_config	mode (int, default -1)	Query (-1) or set the DR mode. 0 = GNSS only (DR disabled), 1 = DR only (inertial navigation without GNSS), 2 = GNSS+DR auto (module decides when to engage DR).

Caution

The dead_reckoning_config tool only works on LC29H(BA) and LC29H(CA) variants. Calling it on AA, DA, or BS modules returns an error response. The module variant can be identified from the model string returned by get_module_info.

EASY / AGNSS (AA Variant)

EASY (Extended Prediction Orbit) is Quectel’s self-generated ephemeris prediction system. It caches satellite orbit data and predicts orbits for up to 3 days, enabling faster time-to-first-fix when the module temporarily loses signal.

Tool	Parameters	Description
easy_status	none	Query whether EASY is enabled and the number of extension days available (0-3 days of predicted orbits stored).
easy_enable	enabled (bool, default True)	Enable or disable EASY ephemeris prediction. Save with save_config to persist.

Power and Performance

Tools for tuning power consumption, filtering behavior, and satellite selection criteria. These work on all variants.

Tool	Parameters	Description
odometer	action (str, default "enable")	Control the GNSS distance accumulator. Actions: enable, disable, reset.
elevation_mask	degrees (int, default -1)	Get (-1) or set (0-90) the satellite elevation cutoff angle. Satellites below this elevation are excluded from position computation. Typical range: 5-15 degrees.
speed_clamping	enabled (bool, default True)	When enabled, the module reports zero speed when stationary. Prevents position drift from being misinterpreted as movement.
gnss_suspend_resume	action (str, default "suspend")	suspend puts the GNSS engine into idle mode (stops tracking but keeps serial alive). resume wakes the engine (similar to hot start).
periodic_mode	mode (int, default -1), run_ms (int, default 1000), sleep_ms (int, default 1000)	Duty-cycle power saving. mode=-1 queries current setting. 0 = disabled (continuous), 1 = smart (stays awake if position uncertain), 2 = strict (fixed timing).

Tip

The elevation_mask tool is useful for reducing multipath interference. In urban environments with tall buildings, setting a 10-15 degree mask filters out low-elevation satellites whose signals bounce off structures. In open sky conditions, a lower mask (5 degrees) maximizes the number of satellites used in the solution.

Resources

MCP resources provide lightweight, read-only status snapshots. Unlike tools, resources are intended for passive monitoring and can be polled by clients that support the MCP resource protocol.

URI	Description	Content
gnss://position	Live position snapshot, updated each fix cycle	Lat/Lon/Alt, fix type, satellite count, HDOP, speed, course
gnss://satellites	Current satellite constellation view	Satellite count plus per-satellite PRN, constellation, elevation, azimuth, SNR
gnss://status	Module status overview	Fix type, satellite count, NTRIP connection state

Resources return human-readable text summaries. For structured data, use the corresponding tools (get_position, get_satellites, ntrip_status).

Example Conversation

You: What module is connected? Show me the satellite constellation.

Claude: I'll query the module and check the sky view.
[Calls get_module_info]
[Calls get_satellites]

The connected module is an LC29H(DA) running firmware
LC29HDANR11A04S, built 2024-03-15. It's the RTK-only variant.

Currently tracking 28 satellites across four constellations:
  GPS:     G02, G05, G07, G13, G15, G20, G24, G29, G30
  GLONASS: R04, R05, R09, R15, R16
  Galileo: E02, E07, E12, E25, E33, E36
  BeiDou:  B11, B14, B23, B26, B33, B37, B44

18 are used in the current 3D fix. Best SNR is 45 dB-Hz on
G05, weakest used satellite is 22 dB-Hz on R16.

You: Disable GLONASS and QZSS — I only want GPS, Galileo, and BeiDou.

Claude: I'll update the constellation configuration.
[Calls configure_constellations with gps=True, glonass=False,
 galileo=True, beidou=True, qzss=False]

Done. GLONASS and QZSS are now disabled. The module will only track
GPS, Galileo, and BeiDou satellites. This change is active but will
revert on reboot — want me to save it to flash?

You: Yes, save it. Then connect to rtk2go.com for RTK corrections.

Claude: I'll persist the configuration and set up NTRIP.
[Calls save_config]
[Calls ntrip_connect with host="rtk2go.com", mountpoint=""]

Configuration saved. Before connecting, here are the mount points
near you from rtk2go.com:

  SFBAY_RTCM3  — RTCM 3.2, GPS+GLO+GAL, 37.78°N 122.41°W
  OAK_GPS      — RTCM 3.3, GPS+GLO+GAL+BDS, 37.80°N 122.27°W

Which mount point should I use?

You: Use SFBAY_RTCM3, no authentication needed.

Claude: Connecting now.
[Calls ntrip_connect with host="rtk2go.com",
 mountpoint="SFBAY_RTCM3"]

NTRIP connection established to rtk2go.com/SFBAY_RTCM3.
RTCM3 corrections are streaming to the module. The fix type
should progress from 3D to RTK float, then RTK fixed within
30-60 seconds. I'll check the position in a moment.

[Calls get_position]

Fix upgraded to RTK_FIXED. Current position:
37.7749182°N, 122.4194023°W, altitude 52.31m
HDOP 0.6, 18 satellites, accuracy is now centimeter-level.

Tool Reference (Complete)

All 20 tools grouped by function, with variant applicability.

Position and Status — All Variants

Tool	Description
get_position	Current position fix with coordinates, fix quality, HDOP, speed, course, timestamp
get_satellites	All tracked satellites with PRN, constellation, elevation, azimuth, SNR, used-in-fix flag
get_module_info	Firmware version, model, build date/time, chip model, chip version

Configuration — All Variants

Tool	Description
configure_constellations	Enable/disable GPS, GLONASS, Galileo, BeiDou, QZSS individually
set_fix_rate	Position fix interval 100-10000ms
save_config	Persist all settings to flash (both PAIR and PQTM config stores)
restart_module	Hot, warm, or cold restart of the GNSS engine

NTRIP — DA, BA, BS Variants

Tool	Description
ntrip_connect	Connect to NTRIP caster; empty mountpoint fetches source table
ntrip_status	Check NTRIP connection state
ntrip_disconnect	Disconnect and cancel RTCM forwarding task

Survey-in — BS Variant

Tool	Description
survey_in_start	Start base station position averaging with duration and accuracy targets
survey_in_status	Survey-in progress with ECEF and WGS84 coordinates, accuracy estimate

Dead Reckoning — BA, CA Variants

Tool	Description
dead_reckoning_config	Query or set DR mode (GNSS-only, DR-only, auto)

EASY / AGNSS — AA Variant

Tool	Description
easy_status	Query EASY ephemeris prediction cache status
easy_enable	Enable or disable EASY technology

Power and Performance — All Variants

Tool	Description
odometer	Enable, disable, or reset distance accumulation
elevation_mask	Get or set satellite elevation cutoff angle (0-90 degrees)
speed_clamping	Enable or disable static speed clamp (report zero when stationary)
gnss_suspend_resume	Suspend or resume the GNSS engine for power saving
periodic_mode	Duty-cycle power saving: disabled, smart, or strict with configurable run/sleep timing

Resources

URI	Description
gnss://position	Live position text snapshot
gnss://satellites	Current constellation view as formatted text
gnss://status	Module status with NTRIP connection state

Local Development with MCP

For developing against the MCP server from source:

# Add local development server to Claude Code
claude mcp add lc29h-dev -- uv run --directory /path/to/lc29h lc29h-mcp

# Test with headless mode
claude -p "What module is connected?" \
  --mcp-config .mcp.json \
  --allowedTools "mcp__lc29h-dev__*"

To run the MCP server with a custom serial port during development:

LC29H_PORT=/dev/ttyUSB0 uv run lc29h-mcp

Tip

When testing with claude -p in headless mode, the --allowedTools flag is required to grant permission for MCP tool calls. Without it, all tool invocations are auto-denied. Use the wildcard pattern mcp__lc29h-dev__* to allow all tools from the development server.